feat: add support for v8 code coverage

TestUtils.ts

@@ -58,6 +58,7 @@ const DEFAULT_GLOBAL_CONFIG: Config.GlobalConfig = {
   testTimeout: 5000,
   updateSnapshot: 'none',
   useStderr: false,
+  v8Coverage: false,
   verbose: false,
   watch: false,
   watchAll: false,

docs/CLI.md

@@ -152,6 +152,8 @@ Alias: `-c`. The path to a Jest config file specifying how to find and execute t
 
 Alias: `--collectCoverage`. Indicates that test coverage information should be collected and reported in the output. Optionally pass `<boolean>` to override option set in configuration.
 
+Cannot be used together with `--v8-coverage`.
+
 ### `--debug`
 
 Print debugging info about your Jest config.
@@ -317,6 +319,19 @@ Divert all output to stderr.
 
 Display individual test results with the test suite hierarchy.
 
+### `--v8-coverage[=<boolean>]`
+
+> _Experimental_
+
+Indicates that test coverage information should be collected and reported in the output. Optionally pass `<boolean>` to override option set in configuration.
+
+This uses V8's builtin code coverage rather than one based on Babel. Note that there are a few caveats
+
+1. Your node version must include `vm.compileFunction`, which was introduced in [node 10.10](https://nodejs.org/dist/latest-v12.x/docs/api/vm.html#vm_vm_compilefunction_code_params_options)
+1. Tests needs to run in Node test environment (support for jsdom is in the works)
+
+Cannot be used together with `--coverage`.
+
 ### `--version`
 
 Alias: `-v`. Print the version and exit.

docs/Configuration.md

@@ -131,6 +131,8 @@ Default: `false`
 
 Indicates whether the coverage information should be collected while executing the test. Because this retrofits all executed files with coverage collection statements, it may significantly slow down your tests.
 
+Cannot be used together with `v8Coverage`.
+
 ### `collectCoverageFrom` [array]
 
 Default: `undefined`
@@ -1121,6 +1123,19 @@ This is useful for some commonly used 'utility' modules that are almost always u
 
 It is possible to override this setting in individual tests by explicitly calling `jest.mock()` at the top of the test file.
 
+### `v8Coverage` [boolean]
+
+> _Experimental_
+
+Indicates whether the coverage information should be collected while executing the test.
+
+This uses V8's builtin code coverage rather than one based on Babel. Note that there are a few caveats
+
+1. Your node version must include `vm.compileFunction`, which was introduced in [node 10.10](https://nodejs.org/dist/latest-v12.x/docs/api/vm.html#vm_vm_compilefunction_code_params_options)
+1. Tests needs to run in Node test environment (support for jsdom is in the works)
+
+Cannot be used together with `collectCoverage`.
+
 ### `verbose` [boolean]
 
 Default: `false`

e2e/__tests__/__snapshots__/showConfig.test.ts.snap

@@ -118,6 +118,7 @@ exports[`--showConfig outputs config info and exits 1`] = `
     "testSequencer": "<<REPLACED_JEST_PACKAGES_DIR>>/jest-test-sequencer/build/index.js",
     "updateSnapshot": "all",
     "useStderr": false,
+    "v8Coverage": false,
     "watch": false,
     "watchAll": false,
     "watchman": true

e2e/__tests__/__snapshots__/v8Coverage.test.ts.snap

@@ -0,0 +1,13 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`prints coverage 1`] = `
+  console.log __tests__/Thing.test.js:10
+    42
+
+----------|---------|----------|---------|---------|-------------------
+File      | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
+----------|---------|----------|---------|---------|-------------------
+All files |     100 |      100 |     100 |     100 |                   
+ Thing.js |     100 |      100 |     100 |     100 |                   
+----------|---------|----------|---------|---------|-------------------
+`;

e2e/__tests__/v8Coverage.test.ts

@@ -0,0 +1,25 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import * as path from 'path';
+import {wrap} from 'jest-snapshot-serializer-raw';
+import {onNodeVersions} from '@jest/test-utils';
+import runJest from '../runJest';
+
+const DIR = path.resolve(__dirname, '../v8-coverage');
+
+onNodeVersions('>=10', () => {
+  test('prints coverage', () => {
+    const sourcemapDir = path.join(DIR, 'no-sourcemap');
+    const {stdout, exitCode} = runJest(sourcemapDir, ['--v8-coverage'], {
+      stripAnsi: true,
+    });
+
+    expect(exitCode).toBe(0);
+    expect(wrap(stdout)).toMatchSnapshot();
+  });
+});

e2e/v8-coverage/no-sourcemap/Thing.js

@@ -0,0 +1,10 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+require('./x.css');
+
+module.exports = 42;

e2e/v8-coverage/no-sourcemap/__tests__/Thing.test.js

@@ -0,0 +1,11 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+const Thing = require('../Thing');
+
+console.log(Thing);
+test.todo('whatever');

e2e/v8-coverage/no-sourcemap/cssTransform.js

@@ -0,0 +1,11 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+module.exports = {
+  getCacheKey: () => 'cssTransform',
+  process: () => 'module.exports = {};',
+};

e2e/v8-coverage/no-sourcemap/package.json

@@ -0,0 +1,12 @@
+{
+  "name": "no-sourcemap",
+  "version": "1.0.0",
+  "jest": {
+    "collectCoverageFrom": ["Thing.js"],
+    "testEnvironment": "node",
+    "transform": {
+      "^.+\\.[jt]sx?$": "babel-jest",
+      "^.+\\.css$": "<rootDir>/cssTransform.js"
+    }
+  }
+}

package.json

@@ -47,7 +47,7 @@
     "isbinaryfile": "^4.0.0",
     "istanbul-lib-coverage": "^3.0.0-alpha.1",
     "istanbul-lib-report": "^3.0.0-alpha.1",
-    "istanbul-reports": "^3.0.0-alpha.4",
+    "istanbul-reports": "^3.0.0-alpha.5",
     "jest-junit": "^9.0.0",
     "jest-silent-reporter": "^0.1.2",
     "jest-snapshot-serializer-raw": "^1.1.0",

packages/jest-cli/src/__tests__/cli/args.test.ts

@@ -65,6 +65,13 @@ describe('check', () => {
       'The --config option requires a JSON string literal, or a file path with a .js or .json extension',
     );
   });
+
+  it('raises an exception if both coverage and v8-coverage is specified', () => {
+    const argv = {collectCoverage: true, v8Coverage: true} as Config.Argv;
+    expect(() => check(argv)).toThrow(
+      'Both --coverage and --v8Coverage were specified, but these two options do not make sense together. Which is it?',
+    );
+  });
 });
 
 describe('buildArgv', () => {

packages/jest-cli/src/cli/args.ts

@@ -17,6 +17,13 @@ export const check = (argv: Config.Argv) => {
     );
   }
 
+  if (argv.collectCoverage && argv.v8Coverage) {
+    throw new Error(
+      'Both --coverage and --v8Coverage were specified, but these two ' +
+        'options do not make sense together. Which is it?',
+    );
+  }
+
   for (const key of [
     'onlyChanged',
     'lastCommit',
@@ -675,6 +682,11 @@ export const options = {
     description: 'Divert all output to stderr.',
     type: 'boolean',
   },
+  v8Coverage: {
+    default: false,
+    description: 'Collect coverage using V8 instrumentation',
+    type: 'boolean' as 'boolean',
+  },
   verbose: {
     default: undefined,
     description:

packages/jest-config/src/Defaults.ts

@@ -65,6 +65,7 @@ const defaultOptions: Config.DefaultOptions = {
   timers: 'real',
   transformIgnorePatterns: [NODE_MODULES_REGEXP],
   useStderr: false,
+  v8Coverage: false,
   watch: false,
   watchPathIgnorePatterns: [],
   watchman: true,

packages/jest-config/src/ValidConfig.ts

@@ -124,6 +124,7 @@ const initialOptions: Config.InitialOptions = {
   unmockedModulePathPatterns: ['mock'],
   updateSnapshot: true,
   useStderr: false,
+  v8Coverage: false,
   verbose: false,
   watch: false,
   watchPathIgnorePatterns: ['<rootDir>/e2e/'],

packages/jest-config/src/__tests__/__snapshots__/normalize.test.js.snap

@@ -143,6 +143,16 @@ exports[`setupTestFrameworkScriptFile logs a deprecation warning when \`setupTes
 <yellow></>"
 `;
 
+exports[`setupTestFrameworkScriptFile logs an error when \`collectCoverage\` and \`v8COverage\` are used 1`] = `
+"<red><bold><bold>● </><bold>Validation Error</>:</>
+<red></>
+<red>  Configuration options <bold>collectCoverage</> and <bold>v8Coverage</> cannot be used together.</>
+<red></>
+<red>  <bold>Configuration Documentation:</></>
+<red>  https://jestjs.io/docs/configuration.html</>
+<red></>"
+`;
+
 exports[`setupTestFrameworkScriptFile logs an error when \`setupTestFrameworkScriptFile\` and \`setupFilesAfterEnv\` are used 1`] = `
 "<red><bold><bold>● </><bold>Validation Error</>:</>
 <red></>

packages/jest-config/src/__tests__/normalize.test.js

@@ -458,6 +458,19 @@ describe('setupTestFrameworkScriptFile', () => {
       ),
     ).toThrowErrorMatchingSnapshot();
   });
+
+  it('logs an error when `collectCoverage` and `v8COverage` are used', () => {
+    expect(() =>
+      normalize(
+        {
+          collectCoverage: true,
+          rootDir: '/root/path/foo',
+          v8Coverage: true,
+        },
+        {},
+      ),
+    ).toThrowErrorMatchingSnapshot();
+  });
 });
 
 describe('coveragePathIgnorePatterns', () => {

packages/jest-config/src/index.ts

@@ -152,6 +152,7 @@ const groupOptions = (
     testTimeout: options.testTimeout,
     updateSnapshot: options.updateSnapshot,
     useStderr: options.useStderr,
+    v8Coverage: options.v8Coverage,
     verbose: options.verbose,
     watch: options.watch,
     watchAll: options.watchAll,

packages/jest-config/src/normalize.ts

@@ -878,6 +878,7 @@ export default function normalize(
       case 'timers':
       case 'useStderr':
       case 'verbose':
+      case 'v8Coverage':
       case 'watch':
       case 'watchAll':
       case 'watchman':
@@ -1009,7 +1010,10 @@ export default function normalize(
   // Is transformed to: `--findRelatedTests '/rootDir/file1.js' --coverage --collectCoverageFrom 'file1.js'`
   // where arguments to `--collectCoverageFrom` should be globs (or relative
   // paths to the rootDir)
-  if (newOptions.collectCoverage && argv.findRelatedTests) {
+  if (
+    (newOptions.collectCoverage || newOptions.v8Coverage) &&
+    argv.findRelatedTests
+  ) {
     let collectCoverageFrom = argv._.map(filename => {
       filename = replaceRootDirInPath(options.rootDir, filename);
       return path.isAbsolute(filename)
@@ -1057,6 +1061,13 @@ export default function normalize(
     newOptions.logHeapUsage = false;
   }
 
+  if (newOptions.collectCoverage && newOptions.v8Coverage) {
+    throw createConfigError(
+      `  Configuration options ${chalk.bold('collectCoverage')} and` +
+        ` ${chalk.bold('v8Coverage')} cannot be used together.`,
+    );
+  }
+
   return {
     hasDeprecationWarnings,
     options: newOptions,

packages/jest-core/src/TestScheduler.ts

@@ -259,14 +259,15 @@ export default class TestScheduler {
   }
 
   private _setupReporters() {
-    const {collectCoverage, notify, reporters} = this._globalConfig;
+    const {collectCoverage, notify, reporters, v8Coverage} = this._globalConfig;
     const isDefault = this._shouldAddDefaultReporters(reporters);
+    const willCollectCoverage = collectCoverage || v8Coverage;
 
     if (isDefault) {
-      this._setupDefaultReporters(collectCoverage);
+      this._setupDefaultReporters(willCollectCoverage);
     }
 
-    if (!isDefault && collectCoverage) {
+    if (!isDefault && willCollectCoverage) {
       this.addReporter(
         new CoverageReporter(this._globalConfig, {
           changedFiles: this._context && this._context.changedFiles,

packages/jest-core/src/lib/__tests__/__snapshots__/log_debug_messages.test.ts.snap

@@ -115,6 +115,7 @@ exports[`prints the config object 1`] = `
     "testTimeout": 5000,
     "updateSnapshot": "none",
     "useStderr": false,
+    "v8Coverage": false,
     "verbose": false,
     "watch": true,
     "watchAll": false,

packages/jest-coverage/.npmignore

@@ -0,0 +1,3 @@
+**/__mocks__/**
+**/__tests__/**
+src

packages/jest-coverage/package.json

@@ -0,0 +1,22 @@
+{
+  "name": "@jest/coverage",
+  "version": "24.9.0",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/facebook/jest.git",
+    "directory": "packages/jest-coverage"
+  },
+  "license": "MIT",
+  "main": "build/index.js",
+  "types": "build/index.d.ts",
+  "devDependencies": {
+    "@types/node": "*"
+  },
+  "engines": {
+    "node": ">= 8"
+  },
+  "publishConfig": {
+    "access": "public"
+  },
+  "gitHead": "0efb1d7809cb96ae87a7601e7802f1dab3774280"
+}